The invention relates to a balancing-vessel type of transducer with intercommunicating chambers, suitable for converting pneumatic signals, however low the strength, into a quantifiable output of whatever nature.
The prior art embraces devices by means of which to meter the shape of metal strip; devices of the type produce a pneumatic signal reflecting the degree of departure from what would be the faultless profile, or the flatness, of such strip.
A pneumatic signal produced in this way needs to be converted ultimately into a mechanical output by way of which to actuate appropriate means for correction of the error detected, and it is at this point that one encounters the major difficulty which hampers successful embodiment of the devices in question, namely: that of designing a transducer that can ensure satisfactory conversion of the pneumatic signal into a mechanical output.
There is a variety of types of transducer currently obtainable through commercial channels, covering both limited and wide pressure-sensing ranges.
Pressure-sensing ranges in the field of application specified above are particularly small, and the prior art transducers most suitable are electric. It has been found, however, that such transducers do not meet constructional requirements where response must be ultrafast, and more important still, direct and proportional.
Response provided by a prior art transducer of the electric type is overlong by reason of the number of conversions needed--viz, the pneumatic signal must be converted into an electrical signal before it can being converted into mechanical output, a process giving rise to a build-up of inertia that lengthens the response. What is more, mechanical output power (in the particular application under consideration, at all events) must be of a certain order, and such a requirement increases inertia in the transducer still further.
The prior art also embraces diaphragm type transducers for use in the field of application in question; the drawbacks with this design are well known, however, inasmuch as the diaphragm material ages and hardens, resulting in fall-off of response, sealing capacity and sensitivity of the transducer as a whole, particularly in those applications with which the disclosure is concerned.
Also of importance is the response curve produced by the transducer, which in the case of prior art types is not genuinely proportional, a fact attributable likewise to the various conversions and the transfer operations that the signal must undergo.
Accordingly, the object of the invention is that of providing a transducer which will be free from the drawbacks mentioned above and capable of an accurate conversion of pneumatic signals, including significantly low strength signals.